1. Field of the Invention
The present invention relates to a multi-feed horn, a low noise block downconverter provided with the same and an antenna apparatus, and particularly to a multi-feed horn used for receiving communication with a plurality of satellites, a low noise block downconverter provided with the same and an antenna apparatus.
2. Description of the Background Art
The communication using an artificial satellite is assigned with a frequency band depending on the intended use. Mainly, the satellite for satellite television broadcasting or the like is assigned with a Ku band (frequency band: 12-18 GHz) and the communication satellite is assigned with a Ka band (frequency band: 26-46 GHz). The broadcasting satellite and the communication satellite are in geostationary orbit around the Earth. In recent years, a plurality of communication satellites which are located close to each other are in geostationary orbit. An antenna provided with a multi-feed horn is used to receive the radio waves from these plurality of communication satellites and the like.
With regard to a multi-feed horn of such an antenna, the multi-feed horn disclosed in Japanese Patent Laying-Open No. 2006-324964 will be hereinafter described. As shown in FIGS. 9 and 10, in a multi-feed horn 101, in order to receive the radio wave from each of three communication satellites, three feed horns 111, 121 and 131 are disposed such that their respective central axes (not shown) are arranged parallel to each other. Feed horns 111, 121 and 131 are provided with proximal end openings 112, 122 and 132, and tip openings 113, 123 and 133, respectively. The conventional multi-feed horn 101 is configured as described above.